Primarily, this investigation will determine the single amino acid(s) and/or combination of amino acids that are essential for growth of Bacteroides melaninogenicus in a minimal media. The most interesting amino acid combination and/or individual amino acid shown to be essential for growth will be selected for study of amino acid fermentation in this organism. In this regard, the stoichiometry will be determined by working out fermentation balances of the various products of this amino acid fermentation, and the pathways involved will be further elucidated by identifying the cofactor requirements and key intermediates.